Transpedicular nucleus replacement system

ABSTRACT

A cannulated screw having a resilient balloon structure capable of supporting compressive and cyclic loads. The balloon provides an artificial disc prosthesis by use of the balloon that mimics the properties of the natural disc by maintaining the intervertebral disc space through a full range of natural motion, absorbing shocks and permitting a natural range of motion.

PRIORITY CLAIM

In accordance with 37 C.F.R. 1.76, a claim of priority is included in anApplication Data Sheet filed concurrently herewith. Accordingly, thepresent invention priority to U.S. provisional patent application Ser.No. 61/784,573, filed on Mar. 14, 2013, entitled “TRANSPEDICULAR NUCLEUSREPLACEMENT SYSTEM”, the contents of which are hereby expresslyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to surgically-implantable spinaldevices and more specifically, to a cannulated screw with inflatableballoon.

BACKGROUND OF THE INVENTION

Intervertebral discs are oblate spherical structures that maintain thespace between adjacent vertebrae. Each intervertebral disc consists ofan outer annulus fibrosus, which surrounds the inner nucleus pulposus.The annulus fibrosus consists of several layers of strong annularfibrocartilage to contain the nucleus pulposus and distribute pressureevenly across the disc wherein a mucoprotein gel serves to absorbshocks.

Deterioration of an intervertebral disc results in limited mobility andcan cause severe pain. For instance, normal aging causes the nucleuspulposus to lose fluid and contract in volume resulting in a reductionin the intervertebral space. Any reduction of space between adjacentvertebrae may put pressure on the nerves of the spinal column. Further,a reduction in volume of the nucleus pulposus reduces the disc's abilityto absorb shock which can result in disc herniation. The bulge of aherniated disc may also put pressure on nearby nerve structuresresulting in pain as well as diminished range of motion.

Surgical options are available including laminectomy and discectomycombined with vertebral fusion and/or dynamic stabilization. However,these surgical options are highly invasive and require prolongedhospitalization and recovery. More recently, artificial disc replacementprosthetics have been used to replace or augment all or part of theremoved or resected intervertebral disc.

The use of an expandable balloon like artificial disc prosthesis filledwith a polymer is known. A joint arthroplasty device can be formed insitu by inserting a hollow device having an aperture and a lumen into atarget joint, and injecting material into the hollow device to form animplant. An artificial/prosthetic facet joint with balloon joint spacecomponent composed of latex, polymer, silicone or the like materials.

What is lacking in the field is a cannulated screw that includes aninflatable balloon to mimic the properties of the natural disc bymaintaining the intervertebral disc space through a full range ofnatural motion and absorb the shocks of daily use.

SUMMARY OF THE INVENTION

A cannulated screw includes a resilient balloon structure capable ofsupporting compressive and cyclic loads. The various embodiments of thepresent invention may be implanted in an anterior, anterior-lateral, ora posterior surgical approach to the procedure. The size of each implantcomponent (in collapsed form) is small enough to be inserted withminimal incisions.

Accordingly, it is an objective of the invention to provide anartificial disc prosthesis by use of a cannulated screw for inclusion ofa balloon that mimics the properties of the natural disc by maintainingthe intervertebral disc space through a full range of natural motion,absorbs the shocks and permits a natural range.

Another objective of the invention is to provide an artificial discprosthesis that is anchored to the vertebral body through the pedicle.

Other objectives and advantages of this invention will become apparentfrom the following description taken in conjunction with anyaccompanying drawings wherein are set forth, by way of illustration andexample, certain embodiments of this invention. Any drawings containedherein constitute a part of this specification and include exemplaryembodiments of the present invention and illustrate various objects andfeatures thereof.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side view of the cannulated screw of the instant invention;

FIG. 2 is a cross sectional view thereof;

FIG. 3 is a perspective view thereof depicting the balloon in aninflated position;

FIG. 4 is an exploded view thereof;

FIG. 5 is a pictorial view depicting the installation of the cannulatedscrew;

FIG. 6 is a pictorial view depicting the installation of the fluidinjecting instrument;

FIG. 7 is a pictorial view depicting the fluid injecting instrumentmounted and expelled; and

FIG. 8 is a pictorial view illustrating the filled ballons.

DETAILED DESCRIPTION OF THE INVENTION

The medical device enables surgical access to the weight-bearing portionof the spine percutaneously through the pedicle. The medical devicedescribed herein comprises a cannulated screw that includes aninflatable balloon to mimic the properties of the natural disc bymaintaining the intervertebral disc space through a full range ofnatural motion and absorb the shocks of daily use.

As such, the medical device described herein provides a better overallapproach to modifying the relationship between adjacent vertebralbodies, without altering the surrounding anatomy, thereby reducing thetime a patient and surgeon have to spend in surgery, and reducing oraltogether eliminating hospitalization following the procedure.

Embodiments of the invention may be practiced without the theoreticalaspects presented. Moreover, the theoretical aspects are presented withthe understanding that Applicants do not seek to be bound by the theorypresented.

It should be understood that numerous specific details, relationships,and methods are set forth to provide a full understanding of theinvention. One having ordinary skill in the relevant art, however, willreadily recognize that the invention can be practiced without one ormore of the specific details or with other methods. The presentinvention is not limited by the illustrated ordering of acts or events,as some acts may occur in different orders and/or concurrently withother acts or events. Furthermore, not all illustrated acts or eventsare required to implement a methodology in accordance with the presentinvention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Definitions: The terminology used herein is for the purpose ofdescribing particular embodiments only and is not intended to belimiting of the invention. Where a range of values is provided, it isunderstood that each intervening value, to the tenth of the unit of thelower limit unless the context clearly dictates otherwise, between theupper and lower limit of that range and any other stated or interveningvalue in that stated range, is encompassed within the invention. Theupper and lower limits of these smaller ranges may independently beincluded in the smaller ranges, and are also encompassed within theinvention, subject to any specifically excluded limit in the statedrange. Where the stated range includes one or both of the limits, rangesexcluding either or both of those included limits are also included inthe invention.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. Furthermore, to the extent that the terms “including”,“includes”, “having”, “has”, “with”, or variants thereof are used ineither the detailed description and/or the claims, such terms areintended to be inclusive in a manner similar to the term “comprising.”

The term “about” or “approximately” means within an acceptable errorrange for the particular value as determined by one of ordinary skill inthe art, which will depend in part on how the value is measured ordetermined, i.e., the limitations of the measurement system. Forexample, “about” can mean within 1 or more than 1 standard deviation,per the practice in the art. Alternatively, “about” can mean a range ofup to 20%, preferably up to 10%, more preferably up to 5%, and morepreferably still up to 1% of a given value. Alternatively, the term canmean within an order of magnitude, preferably within 5-fold, and morepreferably within 2-fold, of a value. Where particular values aredescribed in the application and claims, unless otherwise stated theterm “about” meaning within an acceptable error range for the particularvalue should be assumed.

The following description of the preferred embodiments is merelyexemplary in nature and is in no way intended to limit the invention,its application or uses.

FIG. 1 is a side view of the cannulated screw 10 of the instantinvention. The cannulated screw 10 includes a hollow body 12 having anopen end 14. An outer surface of the hollow body 12 is threaded along anupper portion 16 with a threaded cap 18 for receipt of a locking plug20.

FIG. 2 depicts an expandable body 22 (for example, a balloon) in astored position. The term “balloon” will be used merely as a descriptiveterm, however, it is understood that any expandable body may be used.The balloon extends upward through the hollow body 12 which allowsinsertion through a pedicle without impacting the balloon 22. A ferrule24 fits within an open end 26 of the balloon 22 creating a seal betweenthe balloon and the hollow body 12. As shown in FIG. 3, the balloon isshown in an inflated position. The balloon 22 is forced to pass throughthe ferrule 24 further sealing the balloon 22 to the hollow body 12.Once the balloon 22 is filled with fluid, the locking plug 20 isthreaded into the screw to secure the fluid within the balloon.

FIG. 4 depicts the cannulated screw 10 includes a hollow body 12 havingan open end 14. An outer surface of the hollow body 12 is threaded alongan upper portion 16 with a threaded cap 18 for receipt of a locking plug20. The locking plug 20 may include an o-ring seal 28 to bias thelocking plug in position and further provide for secondary sealing. Theballoon 22 is shown separated from the hollow body 12, the balloon 22 isforced to pass through the ferrule 24 which is used in sealing theballoon 22 to the hollow body 12. Once the balloon 22 is filled withfluid, the locking plug 20 is threaded into the screw to secure thefluid within the balloon. The locking plug 20 may include an o-ring seal28 to bias the locking plug 20 in position and further provide forsecondary sealing, or the threads can be made of an interference fit forsealing.

FIGS. 5-8 provide a pictorial view of the cannulated screw 10 placedthrough a pedicle 50 with an installation tool 52, the tool having adriver end 54 for engaging the threaded cap. It should be noted that anyshape threaded cap may be used and considered within the scope of thisinvention. As shown in FIG. 6, the cannulated screw 10 is installed inthe pedicle 50 with open second end 29 available for receipt of avolumetric material held in a dispenser 60. The dispenser 60 is coupledto the second end 29 and the volumetric material inserted by depressingof the carrier lever 62 filling the balloon 22 positioned between theintervertebral disc space. FIG. 8 is a further pictorial depicting afirst and second cannulated screw 10 & 10′ inserted into the vertebralbody and exhibited balloons 22 & 22′ filled with the volumetricmaterial.

Suitable volumetric materials can be viscous and non-viscous includingsaline, gels, latex, polymers, polyethylenes, silicones, polyurethanes,metallics, ceramics, collagen, hydrogels. Volumetric materials can beradio-opaque contrast agents, allowing fluoroscopic viewing duringinjection into the disc to a known pressure.

The device can also be used to determine the excised nucleus pulposusweight and/or volumetric measurement of the tissue following removal.Corresponding amounts of nucleus replacement material are injected intothe balloon 22 and a replacement for the nucleus can be determined.

Accordingly, in preferred embodiments, a transpedicular nucleusreplacement device comprises a cannulated screw 10 having a hollow body12 with an open first end 14 and an open second end 29, an expandablebody 22 having an open end, a ferrule 24, a threaded cap 18, or alocking plug 20.

The expandable body extends upward into the hollow body from the openfirst end. The ferrule is inserted in the open end of the expandablebody and forms a seal between the open first end of the cannulated screwand the expandable body. The second open end comprises threads forreceiving a threaded cap, the threaded cap comprising threads forreceiving a locking plug. In one preferred embodiment, the threaded capcomprises an O-ring seal. In another preferred embodiment, the lockingplug comprises an O-ring seal. In another preferred embodiment, thethreaded cap and locking plug comprise an O-ring seal.

In preferred embodiments, the balloon is fillable with fluids, fillingbiological agents or other material, the filling delivered to theexpandable body from the open second end of the cannulated screw. Inembodiments, the expandable body may be constructed from any of avariety of flexible materials, thereby enabling the expandable body toexpand and contract to a variety of sizes.

In preferred embodiments, the cannulated screw comprises externalthreading, the external threading extending from about the second openend and extending for about one half to about a quarter of the length ofthe cannulated screw.

In other preferred embodiments, a cannulated screw comprises a hollowbody, a first open end for receiving an expandable body, a second openend for receiving a threaded cap, the threaded cap comprising threadsfor receiving a locking plug. In embodiments, the threaded cap and/orthe locking plug further comprise an O-ring seal.

In a preferred embodiment, the cannulated screw further comprises anexpandable body receivable through the first open end, wherein theferrule is fitted within the open end of the expandable body andprovides a removable seal between the expandable body and the hollowbody of the cannulated screw. In preferred embodiments, the expandablebody is fillable with fluids, filling biological agents or othermaterial, the filling delivered to the expandable body from the opensecond end of the cannulated screw.

In some embodiments, the second end optionally comprises a terminal endhaving a diameter wider than the hollow body for receiving the threadedcap. In other embodiments, the threaded cap is part of the cannulatedscrew.

In another preferred embodiment, the cannulated screw comprises externalthreading, the external threading extending from about the second openend and extending for about one half to about a quarter of the length ofthe cannulated screw.

In other embodiments, the device functions as an artificial discprosthesis. In preferred embodiments, the device is manufactured frombiocompatible components.

It is noted that the medical device described herein may be used forpercutaneous pedicle access, as well as vertebroplasty and kyphoplastysurgeries.

In preferred embodiments, a method of treating a patient requiring animplantable spinal device, comprises surgically implanting the spinaldevice wherein the device comprises a cannulated screw having externalthreading for maintaining the position of the device once it has beenimplanted. The hollow body comprises an open first end for receiving aballoon, wherein the balloon extends upward into the hollow body fromthe open first end; a ferrule provides a seal between the balloon andhollow body; an open second end for receiving a threaded cap, thethreaded cap comprising threads for receiving a locking plug. Once thedevice is implanted, the balloon is fillable with fluids, the ferruleproviding a tight seal between the balloon and the hollow body, fillingbiological agents or other material, the filling delivered to theballoon from the open second end of the cannulated screw. The second endis then sealed with the tightening of the threaded cap and a lockingplug which may comprise an O-ring seal.

It is to be understood that while a certain form of the invention isillustrated, it is not to be limited to the specific form or arrangementherein described and shown. It will be apparent to those skilled in theart that various changes may be made without departing from the scope ofthe invention and the invention is not to be considered limited to whatis shown and described in the specification and any drawings/figuresincluded herein.

One skilled in the art will readily appreciate that the presentinvention is well adapted to carry out the objectives and obtain theends and advantages mentioned, as well as those inherent therein. Theembodiments, methods, procedures and techniques described herein arepresently representative of the preferred embodiments, are intended tobe exemplary and are not intended as limitations on the scope. Changestherein and other uses will occur to those skilled in the art which areencompassed within the spirit of the invention and are defined by thescope of the appended claims. Although the invention has been describedin connection with specific preferred embodiments, it should beunderstood that the invention as claimed should not be unduly limited tosuch specific embodiments. Indeed, various modifications of thedescribed modes for carrying out the invention which are obvious tothose skilled in the art are intended to be within the scope of thefollowing claims.

What is claimed is:
 1. A transpedicular nucleus replacement devicecomprising a cannulated screw having a hollow body with an open firstend and an open second end, an expandable body having an open end, aferrule, a threaded cap, or a locking plug.
 2. The transpedicularnucleus replacement device of claim 1, wherein the expandable bodyextends upward into the hollow body from the open first end.
 3. Thetranspedicular nucleus replacement device of claim 1, wherein theferrule is inserted in the open end of the expandable body forming aseal between the open first end of the cannulated screw and theexpandable body.
 4. The transpedicular nucleus replacement device ofclaim 1, wherein the second open end comprises threads for receiving athreaded cap, the threaded cap comprising threads for receiving alocking plug.
 5. The transpedicular nucleus replacement device of claim4, wherein the threaded cap or locking plug further comprising an O-ringseal.
 6. The transpedicular nucleus replacement device of claim 1,wherein the expandable body is fillable with fluids, filling biologicalagents or other material, the filling delivered to the expandable bodyfrom the open second end of the cannulated screw.
 7. The transpedicularnucleus replacement device of claim 1, wherein the expandable body is aballoon.
 8. The transpedicular nucleus replacement device of claim 1,wherein the cannulated screw comprises external threading, the externalthreading extending from about the second open end and extending forabout one half to about a quarter of the length of the cannulated screw.9. A cannulated screw comprising a hollow body, a first open end forreceiving an expandable body, a second open end for receiving a threadedcap.
 10. The cannulated screw of claim 9, further comprising anexpandable body receivable through the first open end.
 11. Thecannulated screw of claim 10, further comprising a ferrule, wherein theferrule is fitted within an open end of the expandable body andproviding a removable seal between the expandable body and the hollowbody of the cannulated screw.
 12. The cannulated screw of claim 9,wherein the second open end comprises threads for receiving a threadedcap, the threaded cap comprising threads for receiving a locking plug.13. The cannulated screw of claim 12, wherein the threaded cap orlocking plug further comprising an O-ring seal.
 14. The cannulated screwof claim 9, wherein the expandable body is fillable with fluids, fillingbiological agents or other material, the filling delivered to theexpandable body from the open second end of the cannulated screw. 15.The cannulated screw of claim 9, wherein the expandable body is aballoon.
 16. The cannulated screw of claim 9, wherein the second endoptionally comprises a terminal end having a diameter wider than thehollow body for receiving the threaded cap.
 17. The cannulated screw ofclaim 9, wherein the cannulated screw comprises external threading, theexternal threading extending from about the second open end andextending for about one half to about a quarter of the length of thecannulated screw.
 18. The cannulated screw of claim 9, wherein theexpandable body is a balloon.
 19. An artificial disc prosthesiscomprising a cannulated screw having a hollow body with an open firstend for receiving a balloon, wherein the balloon extends upward into thehollow body from the open first end; a ferrule for providing a sealbetween the balloon and hollow body; an open second end for receiving athreaded cap.
 20. The artificial disc prosthesis of claim 19, whereinthe second open end comprises threads for receiving the threaded cap,the threaded cap comprising threads for receiving a locking plug. 21.The artificial disc prosthesis of claim 20, wherein the threaded cap orlocking plug further comprising an O-ring seal.
 22. The artificial discprosthesis of claim 19, wherein the balloon is fillable with fluids,filling biological agents or other material, the filling delivered tothe balloon from the open second end of the cannulated screw.
 23. Theartificial disc prosthesis of claim 19, wherein the cannulated screwcomprises external threading, the external threading extending fromabout the second open end and extending for about one half to about aquarter of the length of the cannulated screw.
 24. A method of treatinga patient requiring an implantable spinal device, comprising: surgicallyimplanting the spinal device wherein the device comprises a cannulatedscrew having a hollow body with an open first end for receiving aballoon, wherein the balloon extends upward into the hollow body fromthe open first end; a ferrule for providing a seal between the balloonand hollow body; an open second end for receiving a threaded cap. 25.The method of claim 24, wherein the second open end comprises threadsfor receiving the threaded cap, the threaded cap comprising threads forreceiving a locking plug.
 26. The method of claim 24, wherein thethreaded cap or locking plug further comprising an O-ring seal.
 27. Themethod of claim 24, wherein the balloon is fillable with fluids, fillingbiological agents or other material, the filling delivered to theballoon from the open second end of the cannulated screw.
 28. The methodof claim 24, wherein the cannulated screw comprises external threading,the external threading extending from about the second open end andextending for about one half to about a quarter of the length of thecannulated screw.